BIOCHEMICAL AND PHARMACOLOGICAL STUDIES ON Morinda lucida AND Eucalyptus camaldulensis
Extracts of eleven plants namely Anarcadium occidentale, Anthocleista vogelii Planch, Alchornea cordifolia, Cassia siberinea, Danielli oliveri, Eucalyptus camaldulensis Dehnh, Mangifera indica, Morinda lucida, Nauclea latifolia, Triplochyton scleroxylon and Carica papaya which are used in Igala (Kogi State, Nigeria) folk medicine for the treatment of typhoid fever and other infective disorders were investigated for their antibacterial activities, using a modification of the agar well diffusion technique. The extracts that showed the strongest antibacterial activities, chloroform extract of Morinda lucida (ML) and n-hexane extract Eucalyptus camaldulensis Dehnh (EC), were further investigated for phytochemical and proximate compositions, bioguided assays, anti-inflammatory actions and toxicological effects. Results obtained show that there is sufficient pharmacological basis for their use for the treatment of typhoid fever and other infective disorders caused by E. coli and S. aureus.
Chloroform extract of M. lucida was bacteriostatic against S. Typhi with a minimum inhibitory concentration (MIC) of ≤ 12.5 mg/ml. The most active fraction however was bactericidal with a minimum bactericidal concentration (MBC) of 100 mg/ml. These results compare favourably to those of standard antibiotics such as gentamicin, amoxicillin and chloramphenicol. Chloroform extract of M. lucida demonstrated anti-inflammatory properties and was not acutely or sub-chronically toxic to rats. N-hexane extract E. camaldulensis had an MIC of ≤ 12.5 mg/ml and an MBC of 25 mg/ml against S. Typhi, and these compare favourably with those of standard antibiotics. The most active fraction had an MIC and MBC of ≤ 12.5 mg/ml and 50 mg/ml respectively. N-hexane extract E. camaldulensis demonstrated anti-inflammatory properties and was not acutely toxic to rats and there is no indication for caution in the administration of the extracts over a period required for treating typhoid fever. There is evidence for potentials of extracts of ML and EC for development of novel anti-typhoid therapy.
BIOCHEMICAL AND PHARMACOLOGICAL STUDIES ON Morinda lucida AND Eucalyptus camaldulensis
1.0 PREAMBLE A number of important pathogens such as Salmonella, poliomyelitis, viral hepatitis and Shigella spp. gain entry through the gastro-intestinal tract. Some of these cause diarrhoeal diseases. Others pass through the intestinal tract to cause diseases in other organs (Lucas and Gilles, 2003). Different pathogens act in different ways. Some produce toxins or other substances which disrupt specific physiological processes, while others invade particular tissues (and may also form toxins) as in Salmonella (Singleton, 1995). Drugs have been used successfully for the treatment of endemic diseases. Infectious diseases are the world’s major threat to human health and account for almost 50, 000 deaths every day (Ahmad and Beg, 2001). The situation has further been complicated by the rapid development of multi-drug resistance by the microorganisms to the antimicrobial agents available. Multi-resistant Salmonella Typhi is widespread in endemic countries (Lucas and Gilles, 2003). Even before the discovery of modern antibiotics and other chemotherapeutic agents, traditional medicine had served as man’s resort when attacked by infective agents such as bacteria and fungi (Crafton, 1983). Herbal medicine has still maintained its popularity in all regions of developing world and its use is rapidly spreading in the industrialized countries (Patrick, 2002).
Herbal medicine represents one of the most important fields of traditional medicine all over the world. To promote the proper use of herbal medicine and to determine their potential as sources for new drugs, it is essential to study in a more intensified way medicinal plants which have folklore reputation (Zulfkar et al., 2009).Plants have the major advantage of still being the most effective and cheapest alternative sources of drugs (Pretorious and Watt, 2001). The local use of natural plants as primary health remedies, due to their pharmacological properties, is quite common in Asia, Latin America and Africa (Bibitha et al., 2002). Over the past 20 years, there has been an increased interest in the investigation of natural materials as sources of new antibacterial agents. Different extracts from traditional medicinal plants have been tested to identify the source of the therapeutic effects (Awadh et al., 2001, El-Faky, 1995). As a result, some natural products have been approved as new antibacterial drugs, but there is still an urgent need to identify novel substances that are active against pathogens with high resistance (Barbour et al., 2004, Recio, 1989, Cragg et al., 1997)
1.1 TRADITIONAL AFRICAN MEDICINE
Traditional Medicine is a major African socio-cultural heritage and it has obviously been in existence for several hundreds of years (Elejuba et al., 2005). By the World Health Organisation (WHO, 1978) definition, traditional medicine is the sum total of all knowledge and practices, whether explicable or not, used in diagnosis, prevention and elimination of physical, mental or social imbalance and relying exclusively on practical experience and observations handed down from generation to generation, whether verbally or in writing. With this description, a few element of traditional medicine includes, various forms of medicines and therapies such as herbal medicine, massage, homeopathy, mud bath, music therapy, wax bath, reflexology, dance therapy, hydrotherapy, mind and spirit therapies, self-exercise therapies, radiation and vibration. Others are osteopathy, chiropractic, aromatherapy, preventive medicine, radiant heat therapy, therapeutic fasting and dieting, spinal manipulation, psychotherapy, etc. It does show that a large country of the size of Nigeria, with diverse cultures and traditions, should be rich in traditional medicine and should have eminent and respected traditional healers to take care of the teeming population.
The traditional healer, as defined by the WHO (2003), is a person who is recognised by the community in which he lives as competent to provide health care by using vegetable, animal and mineral substances and certain other methods based on the social, cultural and religious background, as well as on the knowledge, attributes and beliefs that are prevalent in the community, regarding physical, mental and social well-being and the causation of disease and disability. Traditional medicine has developed in various communities in Nigeria in response to the health needs of the people. The British colonial masters brought in orthodox medicine and, today, both systems of medicine exist in the country. Both have the primary objective to cure, manage or prevent diseases and maintain good health.For most countries of the world, just as we have in Nigeria, a traditional healer may be able to perform many functions thereby becoming more versatile as a healer. However, there are various categories of traditional healers, perhaps specialists known in traditional medicine today and they include herbalists, traditional birth attendants (TBAs), traditional surgeon,bonesetters, traditional medicinal ingredient dealers, traditional psychiatrists and practitioners of therapeutic occultism (Tella, 1976).
According to Tella (1976), Herbalists use mainly herbs, that is, medicinal plants or parts of such plants-whole root, stem, leaves, stem bark or root bark, flowers, fruits, seeds. Sometimes they may use or add animal parts, small whole animal – snails, snakes, chameleons, tortoises, lizards, etc; inorganic residues – alum, camphor, salt, etc and insects, bees, black ants etc. Such herbal preparations may be offered in the form of 1. powder, which could be swallowed or taken with pap (cold or hot) or any drink,
2. powder, rubbed into cuts made on any part of the body with a sharp knife,
3. extract preparation, soaked for some time in water or local gin, decanted as required before drinking; the materials could also be boiled in water, cooled and strained
4. preparation pounded with native soap and used for bathing; such “medicated soaps” are commonly used for skin diseases,
5. pastes, pomades or ointments, in a medium of palm oil or shea butter, or palm kernel oil
6. soup which is consumed by the patient. Herbal preparations may also be administered as enema.
The herbalist cures mainly with plants which he gathers fresh. When seasonal plants have to be used, these plants are collected when available and are preserved usually by drying to eliminate moisture. It is important to stress the relevance of traditional medicine to the majority of Nigerians. Most Nigerians, especially those living in rural communities do not have access to orthodox medicine and it is estimated that about 75 per cent of the populace still prefer to solve their health problems by consulting traditional healers (Adesina, 2010). Where such access exists, the rising cost of imported medications and other commodities used for medicines have posed a big problem. Besides, many rural communities have great faith in traditional medicine, particularly the inexplicable aspects as they believe that it is the wisdom of their fore-fathers which also recognises their socio-cultural and religious background that orthodox medicine seems to neglect.
Plants will continue to remain man’s best source of natural, reliable and active drugs as synthetic drugs often come with side effects and adulterations (Adesina et al., 1998). According to Adesina (1995) there is abundant justification for the use of herbs by the various traditional healers identified.
1.1.1 TRADITIONAL MEDICINE IN IGALA-LAND
Igala is a language of the Yoruboid branch of the Eastern Kwa sub group or the West Benue-Congo subgroup of the Niger-Congo language family, depending on the school of the observer. It is spoken by the Igala ethnic group of North-Central Nigeria. In 1989, an estimated two million spoke Igala, primarily in Kogi State, Delta State and Edo State (Gordon, 2005). Dialects include Ebu, Idah, Ankpa, Dekina, Ogugu, Ibaji and Ife. The Agatu and Bassa people use Igala for primary school. Igala is related to Yoruba.The Igala language as well as Igala culture and tradition has influenced other languages and cultures around the Niger-Benue River -Igbo, Idoma, Edo etc. The home of the Igala people is situated east of the River Niger and River Benue confluence and astride the Niger in Lokoja. The area is approximately between latitude 6°30 and 8°40 north and longitude 6°30 and 7°40 east and covers an area of about 13,665 square kilometers (Oguagha, 1982) The Igalas are the major ethnic group of Kogi State but can also be found in Delta, Enugu and Edo States of Nigeria.